I have to become familiar with a piece of code that I'm going to be working on, but the following code is giving me problems:

$value =~ tr/+/ /;
$value =~ s/%([a-fA-F0-9][a-fA-F0-9])/pack("C",hex($1))/eg;
$name  =~ tr/+/ /;
$name  =~ s/%([a-fA-F0-9][a-fA-F0-9])/pack("C",hex($1))/eg;

[download]

I have no idea what it does! I understand that it's a regular expression, but while I have some understanding of how regular expressions work, I don't understand this, especially the pack("C",hex($1)) part.

Now, what it's supposed to be doing right now is filtering out special characters, but it seems to me that it should be filtering out all the letters of the alphabet after F too, so I'm not sure what's going on. Could somebody help?

In reply to Regular Confuscion by Imagist

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